"They were able to derail the discussion about sugar for decades," Stanton Glantz, a professor of medicine at the University of California at San Francisco who researched the sugar industry's impact on our understanding of health, told The Times.

As an American who recently moved to the UK and grew up at the height of the low-fat diet craze, I find this infuriating. At the same time, I'm not surprised: Dozens of registered dietitians, public-health experts, and obesity researchers I've spoken with in the US over the past few years have repeatedly told me that the sugar in our diets is far worse for us than the fat.

Even though I grew up in California with two health-conscious parents, our kitchen was still subject to the antifat frenzy. Our fridge was always stocked with margarine, not butter; low-fat products (rather than low-sugar or no-sugar-added ones) ruled our pantry. Even today, if I were to take a walk down the "health foods" aisle of my hometown grocery store, I'd most likely find its shelves teeming with low-fat (high-sugar) foods.

Excess sugar, on the other hand (especially in the form of soda) has been linked with several negative outcomes, including weight gain and obesity. A systematic review of 50 years of studies published in the American Society for Clinical Nutrition in 2006 found a link between the amount of sugar-sweetened beverages people consumed and weight gain and obesity.

"The science base linking the consumption of sugar-sweetened beverages to the risk of chronic diseases is clear," the authors wrote in their paper.

Why sugar is the real culprit when it comes to weight gain

When we eat large amounts of sugar and don't balance these calories with those from protein and fat, which the body breaks down more slowly, it can lead to dramatic rises and drops in blood sugar. These "crashes" can cause "hanger," or what's known as being angry and hungry at the same time.

All carbohydrates — bread, cereal, or potatoes — are ultimately broken down into glucose, which circulates in our blood and gives us energy. Sugars get broken down quickly and tend to raise blood glucose most dramatically. And, according to the Centers for Disease Control and Prevention, most of the calories that Americans are getting from sugar are coming from processed foods like cereals, granola bars, breads, and cakes.

Eat more fats — but make sure they're the right kinds

For the paper in which researchers looked at the effects of swapping calories from fat with those from sugar, researchers studied the eating habits of more than 126,000 people who submitted health questionnaires every few years for up to three decades. Next, the authors tested what would happen if those people swapped out 5% of the calories in their diets from saturated fat (the types of fats most often found in meat and dairy products) with one of three other things: A) calories from simple carbohydrates like sugars and refined grains; B) calories from monounsaturated fats, like the kind found in avocados and olive oil; or C) calories from polyunsaturated fats, like the kind found in oily fish and nuts.

Flickr/Jennifer
Not surprisingly, the first option — replacing the calories from saturated fats with calories from simple carbs — was not linked with any observable health benefits.

But the second and third options appeared to be connected with several healthy outcomes. Overall, swapping calories from saturated fats with calories from monounsaturated fats, like the kind found in avocados and olive oil, was linked with a 27% decrease in death of any kind as well as lower rates of heart disease, cancer, and neurodegenerative disease.

This is in line with dozens of recent studies supporting the idea that healthy fats, like those from nuts, fish, and avocados, are good for us, so long as we eat them in moderation. So add them back into your diet if you haven't already, and look to cut back on your intake of refined carbs and sugary snack foods instead.

Snack on nuts. Since they're high in protein, nuts can help stabilize blood-sugar levels, which, if they plummet, can make healthy people feel "hangry" (hungry and angry) and can be especially dangerous for people with diabetes. Nuts are also a good source of fiber, a key nutrient that helps aid digestion and keeps us feeling full.

Cut back on added sugar and refined carbs. Diets that are high in sugar and refined carbs (white rice, sweet snack foods, white bread) and low in whole grains (brown rice, whole wheat) have been linked with health problems, while diets high in whole grains and low in refined carbs tend to be linked with more positive outcomes.

Incorporate oily fish like salmon into your diet. Salmon is rich in omega-3 fats, which help protect our cell membranes, the structure protecting the inner components from their outside environment. They are also the building blocks of the hormones that regulate blood clotting and inflammation.

Eat avocados. While they're high in fat and calories — just half of one medium avocado is 120 calories, about the equivalent of a slice of bread — avocados are low in sugar and rich in fiber. So add a few slices to your next meal.